Many appliances operate using liquid or gas fuel. For example, many home grills operate using liquified propane stored in pressurized tanks. A problem arises, however, because the tanks are often opaque containers. Thus, the volume stored in the tank cannot be visually discerned. While some appliances using such tanks include a pressure gauge, many do not. Thus, in a conventional appliance, there is typically no readily discernable way to determine the volume of the contents of the tank.
A number of inventions have been created to address this problem. Most use a method and device in which a spring is biased against a tilted tank. As the tank empties, the weight decreases and the spring causes the tank to tilt in the opposite direction.
One drawback of this type of system is that no indicator is given and the user is expected to understand the significance of the tilted tank. Also, this type of system is prone to inaccurate readings if the pivot around which the tank tilts sticks or otherwise cannot rotate freely. Additionally, the amount of tilt may inaccurately reflect the quantity contained in the tank if the tank is improperly positioned on the system because the amount of tilt will depend on the length of the moment arm around the pivot.